1. Field of the Invention
The present invention relates to compression assembly hand tools for attaching a connector to a coaxial cable by compressing the connector in a direction parallel to the axis of the cable. More specifically, the present invention relates to compression assembly tools that minimize the opening angle of the handles so that they operate in the range where the hand can apply the greatest closing force while still providing a long compression stroke. The invention also relates to compression assembly hand tools, which are preferably capable of compressing connectors of different sizes.
2. Description of Related Art
One known type of compression assembly hand tool is used to attach a connector to a coaxial cable by compressing the connector in a direction parallel to the axis of the cable. A variety of connector designs are available that are attached by compression assembly tools that apply the compression force in this axially parallel direction.
Connectors designed to be attached in this manner often have two components that slide into axial engagement when the axial compression force is applied. As the two components engage axially, one is forced radially inwards by the other to grip the coaxial cable and make a permanent connection.
An alternative connector design attached by a compression assembly tool of this type includes a weakened section of the body that is shaped to collapse radially inward as an axial compression force is applied. The inward collapse of the connector body permanently attaches the connector to the coaxial cable.
A conventional design for compression assembly hand tools includes a moving lever handle that rotates relative to the body of the tool and drives a link connected to the back end of an axially sliding plunger. The back of the connector adjacent to the emerging coaxial cable is supported by a compression surface on the tool body. The front of the connector is compressed towards the back of the connector by the axially sliding plunger as the handles are closed.
Examples of tools of this type are seen in U.S. Pat. No. 7,210,327 issued on May 1, 2007, U.S. Pat. No. 6,820,326 issued on Nov. 23, 2004, and U.S. Pat. No. 5,934,137 issued on Aug. 10, 1999, all of which are assigned to the assignee of the present application, Capewell Components Company, LLC of Cromwell Conn.
In order to achieve the compression force needed for such hand tools, the tool must be designed so that force applied to the moving lever handle by the user is multiplied as it is applied to the sliding plunger. One conventional method of achieving this force multiplication is by designing the tool so that the angle of rotation of the moving handle as it moves between open and closed positions is as large as possible. The greater this opening angle, the farther the lever handle moves and the less force that must be applied.
Typically, the handle opening angle is greater than 30 degrees, and often it is more than 40 degrees. Although the increased opening angle reduces the hand force that must be applied, it produces a tool that may be awkward for some users to operate. The larger the opening angle, the larger the hand required to simultaneously grasp both handles. Some users may initially require two hands for tools with very large handle opening angles.
Conventionally designed compression assembly tools achieve mechanical advantage by connecting one of the pivots driving the plunger at a point near the middle of the moving lever handle. In these designs, the lever handle extends well beyond the pivot it drives to maximize the leverage applied by the handle. However, the mechanical advantage achieved by extending the handle beyond the pivot it drives, i.e., by connecting the driving pivot at a point near the middle of the moving lever, results in an undesirably large handle opening angle.
The problem with large handle opening angles is accentuated when longer handles are used as may be desirable for some tools required to compress larger connectors. The longer handles are not only more difficult to grasp, they may create clearance problems when used in limited spaces.
Another problem with large opening angles is that a human hand can apply progressively greater force as the hand closes. When the opening angle is large, the user can only apply limited force to the handle. A compression assembly tool that can compress connectors without requiring a large opening angle would be desirable, as it would allow the user to operate the tool in the range where the human hand can most effectively apply the greatest force.